In 1943 the need for a lighter and handier version of the Lee Enfield rifle became clear throughout the British Commonwealth, and experimentation began in Canada, Britain, and Australia. The work in Britain would culminate in the No5 Mk1 rifle, but the Canadian arsenal at Long Branch would try some different ideas first. Several different experimental prototypes were made with varying features, but they all shared the idea of substantially lightening the rifle without shortening it very much. This was done by removing metal anywhere possible, most obviously including the elimination of the stock socket and the use of a single piece stock in place of the traditional two piece Enfield stock.
These modifications, also including an aluminum alloy trigger guard, were able to cut 25% of the weight from the rifle, and do so without a significant loss in accuracy. However, I suspect the resulting rifle would have proven far too fragile for combat use had it been adopted. The stock is surprisingly light and thin at the wrist, and it feels like it would not take much force to crack it. In addition, lightening cuts down the length of the hand guard made it quite susceptible to warping with heat and humidity changes.
Ultimately the Long Branch Lee Enfield carbine experiments would be abandoned as the No5 “Jungle Carbine” was adopted instead.